The present invention concerns vehicle carriers and, more particularly, carriers which employ a tilting vehicle bed up or down which vehicles move when being respectively loaded onto or unloaded from the carriers, and is essentially embodied in a "Disclosure Document" entitled "Trailer", Document No. 176750, received in the U.S. Patent and Trademark Office Sept. 3, 1987.
The prior art abounds with carriers, either truck or trailer mounted, which employ tilting vehicle beds. So far as is presently known, however, the prior art of that nature most pertinent to the present invention resides in U.S. Pat. Nos. 4,514,131; 4,655,671; and 4,109,809. The first of these patents discloses a truck-mounted carrier having a sub-frame 14 to whose rear end is pivoted at 24 a lift frame 18. A load bed 28 is longitudinally slidable on the lift frame 18. As a ram 32 tilts the lift frame 18 about its pivot 24 another ram 30 moves the load bed 28 rearwardly to the ground relative to the lift frame 18. A like sequence restores the frame 18 and bed 28 to the horizontal. The rearward movement of the load bed 28 extends its effective length so as to provide a less abrupt angle between the ground and the bed 28. But power means, the rams 30 and 32 and controls 50 are needed in order for the foregoing to be accomplished. The second patent features a boat loading and unloading trailer having a tilting section 2, hinged at 5, and slidably receiving folding ramps 7 and 8 on which rides a wheeled cradle 4. When launching a boat the ramps 7 and 8 are slid rearwardly, presumably manually or by power means, and the cradle 4 with the boat moved back past the hinge 5, whereupon the ramp 7 tilts downwardly and the ramp 8 forms a platform in the water supporting the cradle 4. Here again substantially the same effect results as in the U.S. Pat. No. 4,514,131 but either power or manual means are necessary to slide the ramps 7 and 8 back and forth. The third patent describes a trailer having ramps 26 and 27 hinged at 35 which are tilted between horizontal and inclined positions by fore-and-aft movement of the vehicles 12 owing to the change in the center of gravity about the hinge 35. The ramps 26 and 27, however, are relatively short, making an abrupt angle with the ground, and requiring a separate "bed" (the turntable 33) on which to store the vehicles. The result is a trailer of extensive overall length.
The primary object of the present invention is thus to provide a vehicle carrier in which the bed not only serves as a bed on which to carry a vehicle but also as a ramp by which the vehicle can be automatically loaded and unloaded, all, however, without the need of any manual effort or of any power means such as hydraulic rams, winches or the like, in order to do so.